Fouling Mechanisms and Heat Transfer in Thermal Systems

Fouling refers to the unwanted accumulation of solid, liquid or biological deposits on heat-transfer surfaces, which impedes thermal performance and raises operational costs. Key mechanisms include particulate fouling driven by thermophoretic and inertial forces, crystallisation or scaling from supersaturated solutions, corrosion products and biofilm growth. These deposits increase thermal resistance and pressure drop, reducing heat-transfer coefficients and overall system efficiency. Factors governing fouling rate and deposit morphology encompass fluid velocity, temperature gradients, particle size and concentration, surface roughness and chemistry. Predictive modelling—ranging from empirical correlations to computational fluid dynamics (CFD) with discrete phase tracking—has advanced understanding of deposit formation, distribution and removal. Experimental studies employing controlled bench-scale rigs complement numerical predictions, enabling parametric investigations of fouling under realistic conditions. Globally, fouling mitigation is pivotal for power generation, refrigeration, automotive exhaust recovery and HVAC, as well as for minimising fuel consumption and emissions. Strategies such as periodic cleaning, anti-fouling coatings, surface modification and optimisation of flow conditions interplay to maintain thermal performance. The convergence of rigorous experimentation, refined modelling and novel materials underpins current efforts to predict, monitor and control fouling for enhanced energy sustainability.

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Fouling Mechanisms and Heat Transfer in Thermal Systems publication trend

The graph below shows the total number of articles in fouling mechanisms and heat transfer in thermal systems across all publications each year (not limited to Nature Index journals).

Technical terms

Fouling: Deposition of unwanted solids, liquids or biological films on heat-transfer surfaces, leading to increased thermal resistance and pressure drop.

Thermophoresis: Migration of particles from hot to cold regions due to temperature gradients, a dominant mechanism in particulate fouling.

Thermal resistance: Opposition to heat flow across a material or interface, often increased by deposit layers.

Fin efficiency: Ratio of actual to ideal heat transfer from a finned surface, reduced by fouling.

Heat-transfer coefficient: Measure of convective heat-transfer rate per unit area and temperature difference, diminished by surface deposits.

References

1. Numerical Study on Particulate Fouling Characteristics of Flue with a Particulate Fouling Model Considering Deposition and Removal Mechanisms. Energies (2022).
2. Analysis of Soot Deposition Effects on Exhaust Heat Exchanger for Waste Heat Recovery System. Energies (2024).
3. Deposition Distribution and Thermal Resistance Analysis of Fins in Heat Exchangers. Energies (2024).
4. Experimental study and analysis of an air-cooled condenser with the fouling on the heat exchange surface for small-scale commercial refrigeration systems. International Journal of Air-Conditioning and Refrigeration (2023).